Monroe County planning staff is recommending approval of a dredging plan for privately owned channels and canals, despite opposition from research scientists and environmental groups who say it will destroy marine life habitat.

The County Commission will vote on the plan Thursday in Marathon.

The owners of a small island off Duck Key have asked Monroe County to amend its land-use plan to create a new category county planners are calling "redredging," which would allow them to dredge a 30-foot-wide by 700-foot-long privately owned channel.

The county's comprehensive plan prohibits new dredging, only allowing maintenance dredging in areas without seagrass and hard-bottom habitats. Maintenance dredging is only allowed in public navigation channels, constructed or maintained by a federal, state or local government agency.

The plan is being opposed by the The Lower Keys (Fishing) Guides Association, the Florida Keys environmental group Last Stand and several South Florida research scientists.

The Lower Keys (Fishing) Guides Association contend the plan would cut the seagrass meadow in half.

"Fragmented seagrass beds do not provide the same ecological values as continuous meadows," the Guides Association wrote in a letter to the county. "Boat traffic that would then be generated would continue to erode away the remaining seagrass bed from the motion of boat wakes and by re-suspending bottom sediment. The seagrass, sponge and coral communities that would be destroyed by dredging serve important functions in filtering the water and maintaining offshore and nearshore water quality which is extremely important to the health of our coral reefs."

Seagrass supports both commercial and recreational fisheries, and the Florida Department of Environmental Protection has estimated each acre of seagrass in Florida has an economic value of approximately $20,500 per year, the guides said.

If the proposal is passed it will "lead the way to legalizing previously illegal dredging," they wrote.

Last Stand board President Naja Girard called opening the Keys to more dredging "backward" thinking.

"The fact that in the 1950s -- a time before we as a society had become environmentally conscious -- an area in what is now a national marine sanctuary had been sloppily dredged, should not serve as justification for the decimation of what is now a healthy thriving seagrass meadow," Girard told The Citizen.

The development company's biologist, Sandra Walters, contends the project wouldn't open the Keys to widespread dredging of private channels because each property owner wanting to do so would have to submit their own plan that would also need county and state approval.

Walters argued there is a lot of misinformation being disseminated to the public.

"It's unfortunate that people out there lobbying and not provided all of the information," Walters said.

County planning staff's research found that only 20 properties would be able to apply for new the dredging category, Walters said.

The Walker's Key channel was first dredged in the mid-1950s to about 5 to 6 feet, Walters said.

The channel since accumulated extensive sediment, and currently the depth ranges from 0.47 feet to 2.86 feet, with an estimated average depth of about 1.5 feet, according to the county.

If approved, the county would allow the Little Conch Key Development Co. to dredge the channel no deeper than 4.5 feet, County Planner Mayte Santamaria said.

The development company also agreed to give to the state 26 acres of sensitive bay bottom and mangroves around the channel for a "conservation easement," Walters said.

The Planning Commission recommended approval of the new dredging category when it met in November. County planning staff also recommends approval.

Also on Thursday, the commission will vote on a comprehensive plan change that would allow for hotels on Safe Harbor on Stock Island. The comp plan amendment would change the harbor's Future Land Use Map category for 18 pieces of waterfront property from industrial to mixed-use commercial, which would legalize a hotel on each of those 18 parcels.

In exchange, the owners agreed to set aside 35 percent of the upland area for traditional working waterfront activities, preserve 20 percent of existing wet slips for recreational and commercial boats and put aside 10 percent of new wet slips for recreational and commercial vessels.

They also agreed to preserve public access to the water along the harbor.

The new rule says to "limit permanent residential development to commercial apartments or employee housing" and limit commercial retail uses to less than 5,000 square feet.

The commission meets at 10 a.m. Thursday at the Marathon Government Center.